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A Buyers Guide and FAQ to Replacing Your Cooling & Heating Systems

And since there’s lots of decent info on there, go ahead and take a picture of it with your smart phone, so you can refer to it later.

Now, use the Brand and Serial number to find out how old your unit by looking it up online. Just Google “[brand] serial number [actual number]

You’ll find information on how to tell the date of manufacture for your system from the serial number.

We know, this should be easier — why not put the date of installs right on the system? — and with Plumbline Services installs, we do exactly that, but it’s not an industry wide practice.

So, you’ll probably have to look date of manufacturer up by serial number online.

Now you know the age, you can get a general idea of how much life ought to be left on your system.

Most AC systems last between 10 and 15 years, depending on climate, quality of install, and maintenance.

And while it may be tempting to try to “drive your old one into the ground” and only replacing it on breakdown, there are some huge advantages to replacing your old system towards the end of its expected life BEFORE it breaks.

First, most systems break when stress tested for the first time in a season — during the first string of super-hot days of the summer.

And that means most trustworthy AC companies will be booked out, sometimes for weeks, and you’ll have to go without AC waiting until they can get to you.

Second, there are no deals to be had on AC units during the summer, just like there are no deals on furnaces during the winter.

By replacing an old unit before it dies, you can schedule your replacement during the spring or fall and eliminate the need to be too hot or too cold in your own home.

Plus, you’ll usually get a much better price on the new unit.

How should you really decide whether to repair or replace your air conditioning system or furnace?

This tends to come down to three big variables:

  1. How old is your system vs. expected life?
  2. What's broken and how expensive will it be to repair?
  3. How suited is your old system to your needs?

Industry standard is for an AC system to last between 10 and 15 years, depending on climate, quality of install, and maintenance.

So, if your old system is under 10 years old, you’ll generally lean more towards repairing than replacing, whereas older systems are better bets for replacement.

Then there’s the cost of repair. If the repair costs are between, say, 40% to 50% of the worth of the system, then it typically makes more sense to replace.

New, most systems will range from $5,500 to $16,000, depending on size and features. Of course, systems also depreciate as they age.

So, in general, once a repair runs beyond, say $2,000, you might start looking towards replacement, depending on the age, size, and sophistication of the system

Of course, if the system was installed properly and is relatively new, it should be under warranty.

But you might be surprised how many seemingly reputable AC installers don’t follow all the manufacturer specifications for installing and commissioning a new system, and so void that manufactures warranty from the start

Plumbline Services installs systems right, so our customers get both the manufacture’s performance AND lifetime warranties.

In terms of what’s broken, total failure of any major component— a heat exchanger coils, compressor, multiple blower motors — is usually a good sign that the entire system ought to be changed out.

Plus, those components tend to be more expensive and more labor intensive to fix, which plays into expense of repair vs. expense of replacement.

Finally, you should look at how well suited your old system is to your needs:

  • Is your system an older, energy hog, or is it already a higher-efficiency model?
  • Does it have a harder time keeping you comfortable at night (i.e., do you have to nudge the thermostat down at night) or in "shoulder" seasons?
  • Do you wish you had a dual zone unit that could be set differently for upstairs and downstairs?
  • Is your old unit sized properly for your house to begin with?
  • Has it already broken down this season or last season?

A unit that wastes energy, doesn't keep you comfortable, and/or isn't sized properly make a lot more sense to replace earlier rather than later.

And, yes, the sales rep and promos are telling you the truth that the switch from an older 10 SEER unit to a high efficiency unit can sometimes pay for itself from savings.

Does the brand really matter when it comes to air conditioners and furnaces?

Every AC pro who has a favorite or preferred brand will tell you why theirs is hands-down the best, but in general… it doesn’t matter so much which top brand you buy, so long as you DO buy a top brand, rather than an off-brand.

See, top brands only sell to and do business with licensed professionals.

And that means if your installer is using an off-brand, he just might be an unlicensed or un-established “chuck-in-a-truck.”

So, while those guys might offer to install a new system for less money, they’re also not offering you any deals — those savings are coming out of the quality of your new unit, the quality of the install, and the fact that you’ll have no manufacturer's warranty and no one to call if and when your system breaks down or under performs.

A fundamental truth about buying new AC systems is that the installation matters as much as the equipment.

And there are a lot of shortcuts installers can take to make life easier on them — allowing them to get the install done faster and with a lot less work — that can rob your system of 30% or more of it’s performance, energy efficiency, and expected service life.

Our Advice: DO get a known brand but spend more time getting a top-quality install team and less time worrying about which top brand you get.

How will you know if the install team is top quality?

See if they meet the manufacturers installations requirements to provide their customers with the performance and service life warranties.

What Types of Advanced AC Technology Actually Matters (And What Doesn't)?

You may know that the major components of an AC system are the heat exchangers, the compressor, and the blower motors — and those components are where it’s worth getting upgraded technology.

The old adage “they don’t make ‘me like they used to” is not only wrong when it comes to AC systems, it’s the exact opposite — the new technology not only makes the systems perform better, with greater efficiency, it also helps the systems last much longer.

So, let’s look at some of these new technologies:

Variable Speed Compressors: Just like with a car, it’s the starting and stopping that puts the most wear and tear on a compressor.

And traditional compressors do a lot of starting and stopping — there single speed, so they’re either on or off.

So, they run until the temperature hits whatever’s set on the thermostat, then they stop. Rinse, wash, repeat.

This not only creates a lot of wear and tear, but it hurts the system's ability to dehumidify your home’s air at night and during late spring and early fall.

Whenever the system is off more than on — shorter run times for the compressor — it’s not dehumidifying.

You’ll notice this if you feel like bumping your thermostat down at night to be comfortable.

Variable Speed Compressors fix this by being able to run at half-speed or quarter speed. This lengthens the run-time of the system, reducing start and stop wear. It also dehumidifies your home better.

And because starting and stopping not only create wear, but suck up a bunch of energy, it leads to a more energy efficient system.

Variable Speed Blowers: When your fans can adjust to demand in order to keep your system breathing properly, not only will your home be more comfortable, but your system will operate much more efficiently and generally last longer.

Normal fans only have one speed, so they can’t “flex” to make up for increased demand or changing conditions, and this can lead to improper airflow, which not only leaves your home less comfortable, but places stress on your system.

Variable Speed fans can change speed to overcome changing pressures, or changing demand, which helps your system “breath” better — leading to longer life and better performance for your AC system, and greater comfort for you.

Advanced Technology Heat Exchangers: Different brands will have different technologies — Spine-Fin, Quantum Coil, etc. — that they’ve invested in, but all of the major brands DO have advanced technology heat exchangers and they all work to exchange heat more efficiently and to last longer in use.

Think of this like “future-proofing” your new AC system. It’ll serve you longer and with better performance if you elect for this upgrade.

Your Advertising/Promotions/HVAC Design Consultants Claim the Energy Savings will "Pay For" the new system. Is that true?

Most probably, yes, it’s true.

The actual numbers will depend on your current systems efficiency vs. your new systems efficiency, as well as on how hard you use your system and how much energy costs, as well as what kind of rebates, tax incentives, and financing you get.

But, yes, most of the time, moving from an older 10-13 SEER system to a newer 16-22+ SEER system will save you a bundle on energy costs, likely equaling or almost equaling your monthly payment on the new system.

SEER stands for Seasonal Energy Efficiency Ratio, and it’s a measure of how much heat a unit can remove from your home (measured in BTUs) per watt-hour of electricity.

So, to keep the math easy, let’s use an example of comparing a 20 SEER unit to a 10 SEER unit. That’s double the efficiency, which means it would use half the energy.

If summer-time usage of AC is 70% of your energy bill, you could reduce your total electric bill by one third during summer months.

When you compare that monthly savings to your monthly payment for the new system, they often will equal out or nearly equal out.

And since most people upgrade their furnace or heat pump at the same time as their AC unit, the savings extend pretty much year-round.

An HVAC Design Consultant can help you crunch the numbers for your specific home, selected new units, and energy costs. Just make sure to work with a HVAC expert you can trust.

Or call us: 303-436-2525

Do I really need new duct work? What's wrong with using the old ducting?

HVAC systems need to breath. Proper and balanced airflow and coolant flow is essential for maximum efficiency and service life.

If your old system wasn’t breathing properly, your comfort advisor will likely recommend that you replace your return air ducting.

Beyond that, leaky ducting ends up costing you money to air condition your attic, which is a complete waste. It also lets in dust and contaminates your home’s air.

So, when evaluating your old ducting, professional installers will look to see:

  • Is it properly sized?
  • Does it allow for proper air flow? (No tight corners, or lack of plenums, or spaghetti-noodle ducting layouts)
  • Is it clean and properly sealed?
  • Is it in good shape or rapidly degrading?

If your old system was installed properly, you’ll usually be able to re-use your existing ducts.

If it wasn’t, your techs may advise you to replace your return air system (to help your new system breath properly) or the entire duct system, to ensure you have clean cool air circulating properly throughout the whole home.

If you have a room or two in your home that doesn’t get proper cooling or heating, now is the time to let your comfort advisor and installation crew to know about it, so they can fix the situation.

Most duct work should last a long time, but certain types of fiberboard ducting that were popular in the 80s and 90s have a tendency to degrade and should probably be replaced, if possible.

This is yet another situation where you really want to work with HVAC professionals you can trust.

If you're in the Denver area and need HVAC help, contact Plumbline Services! We have been serving Denver and the surrounding area since 1998 and provide expert heating and air conditioning repair, installation and service you can count on.


I'm not sure how old my AC System is. How can I check? How long do most systems last?

You can check this yourself, but you’ll have to do a little sleuth work.

First, locate either your system’s air-handling unit (typically located inside your house) or the compressor (the outside unit) and look for the data plate or sticker. It’ll look something like this:

Need help from a Colorado Plumbing, Heating, Cooling, or Electrical Specialist? 

For your convenience, you can request an appointment in one of two ways:

  • Call us at (303) 436-2525 for immediate assistance.
  • Click on the button below to schedule your appointment online.


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